Concrete – How to fix sticky KILZ primer

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Has anyone ever had problems with an oil-based primer like KILZ being sticky or not drying correctly?

We removed some vinyl tiles and mastic from a basement laundry room floor (concrete) using BEAN-e-doo. After that we washed several times with a degreaser and dried the room with a dehumidifier for a day. It's a dry climate here so the floor felt dry, but there was a grid-patterned dark stain where the tiles had been. We had some KILZ Original Primer leftover from covering pet odors in other rooms, so I decided to prime it with that.

After a more than a week, most of the floor is fine, but there are patches of sticky primer (it feels solid, but sticky like tape), and there are a few small areas where the primer is still a bit soft and tacky.

I just read the KILZ page about Blocking Stains:

Although it may seem counterintuitive, water-based primers are the recommended choice for sealing oil soluble stains.

My guess is that residue from either the mastic, the BEAN-e-doo or both is still embedded in the concrete, and I should've used a water-based primer.

What is the best way to proceed?

  1. Give the primer more time to dry
  2. Paint over it with water-based primer
  3. Strip the floor and start over

It's about 350 square feet, so really don't want to strip it, but I also don't want to create a bigger mess by doing the wrong thing. My hope was to prime it and paint it with something durable.

Best Answer

The problem you are having is not uncommon. It is a basement floor so I'm guessing below grade. There should have been a layer of 10mm poly under the floor when it was poured but either way concrete leaches moisture. This is a contributor to your problem.

If you didn't thoroughly wash the floor (I mean powerwash) with a bleach based cleaner you will have a hard time getting any product to last. If you can't pressure wash, scrub as best as you can and use an etching acid or solution. Kilz will dry, unless there's moisture or dirt underneath. Will have a harder time overcoming moisture as it doesn't have near the penetrating properties as a specific product like drylok does. But for a floor, I prefer the lasting quality of a concrete epoxy.

I know it's not your most favorable thought (starting over) so ultimately it's up to you. The right prep and technique with a product specific to the job may save you the hassle of ever doing it again. Best of luck!